4. Myth: Most pot smokers are heavy users
Fact: Between 40 and 50 percent of people who have tried marijuana report a lifetime total of fewer than 12 days of use. About one-third of pot smokers report having used mariajuana for 10 days or less in the past year. About 6 million of America's 30 million users over the age of 12 use pot on a daily or almost-daily basis according to household survey data – a fifth of those who say they have used marijuana in the past year – but they account for about 80 percent of all marijuana consumed.